Portable personal devices, such as mobile telephone handsets and PDAs etc., are becoming smaller. These devices typically use integrated optical touch panels (OTP) functioning with icons and virtual keypads thereby saving space by eliminating the mechanical keypad.
The transceivers of conventional OTPs are made-up of transmitters (typically Light Emitting Diodes or Laser Diodes) and detectors (typically Photo Diodes or PIN Diodes) operating in conjunction with a display device (typically a liquid crystal display (LCD)). Since the signals (light, etc.) from the transmitters to the detectors must pass above the surface of the display, the transceiver elements (transmitters and detectors) are mounted above the plane of the display. This, then, requires the transceiver elements to be mounted on risers that are at right angles to the plane of the display. Presently, manufacturing processes require separately constructed risers that are then attached to the sides of the display. This construction is costly, from both the material and building time standpoints. Also alignment of the transmitters with the detectors and with the display surface presents problems.